Heats of immersion of zeolites in n-alcohols

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Abstract

The heats of immersion in n-alcohols of zeolites NaY, 5A and ZSM-5 and the kinetics of the
immersion process have been determined using a Calvet MS-70 microcalorimeter. The specific heat
of immersion decreased non-linearly as a function of chain length of alcohol for NaY and 5A. In
contrast, the specific heat of immersion passed through a maximum at n-pentanol for ZSM-S. The
specific immersion time as a function of chain length of alcohol showed an apparent linear increase
in the order 5A > ZSM-S > NaY. NaY showed almost no increase. The effects of sample
evacuation temperature and butyl alcohol isomer bulk on the heats of immersion were also
investigated. These results were interpreted in terms of molecular accessibility of the wetting liquid
into the pores of the zeolites and in terms of the Si/Al ratio of the zeolites. The overall kinetics of
immersion appears to be first order.